While I have a (kneejerk?) dislike of ‘emotion based’ moralizing this wasn’t what I was hanging the argument on here. Let’s just abstract away from the fact that we are talking about the ‘emotion based’ moral reaction and merely call it process B. Now I think it is fair to say the following things about process B.

1) Those moral judgements we made in the past that we now find abhorrent (refusal to contemplate autopsies, slavery, avoidance of menstruating women, etc..) were primarily the direct result of applying process B.

2) Those judgements made using process A (the other one) that we accepted in the past are much more likely to endure.

3) Process B is the result of a certain type of neurological process, i.e., process B is not some arbitrary grouping we created after the fact it’s a natural kind of moral reasoning.

4) Process B is atomic, i.e. process B doesn’t rest on chains of inference or justification that might potentially allow us to find some other common point of failure for the misguided moral judgements our culture made in the past.

Now one response (and I feel a strong tug here) to this is simply to shrug one’s shoulders and say that principled moral reasoning is hopeless and we should give up the idea that moral philosophy has useful advice about ethics. On the other hand suppose you believe that moral philosophy should indead allow us to identify the biases in our moral judgements and eliminate them leaving us with a true moral theory.

Well in this case the fact that process B seems to frequently lead to faulty results and is the result of a common neurological cause should lead us to conclude that process B itself is the biasing factor. Now you might protest that surely it isn’t logically required to throw out all of process B. Maybe you could say that process B is misleading except in special circumstance K?

Perhaps but I would argue then you’ve given up the idea that moral philosophy can lead you to a principled answer. I don’t see how you can hope for a more clear cut case of a sort of logically consistant moral reasoning being seen to give flawed moral advice so if you won’t throw out process B it seems hopeless that you will ever have a principled ground to throw out certain kinds of moral intuitions.

In other words what is doing the real work here is the assumption that moral philosophy is actually a sort of serious theorizing about moral inference not merely a collection of examples that tweak our intuitions.